Speaker
Description
Dynamical heterogeneity, fractality, and topology are central concepts in modern condensed matter physics. Their origin is typically rooted in very different physical settings and microscopic mechanisms, such as glassy dynamics, quenched disorder and the absence of symmetry breaking. We show here that a simple, clean lattice model -- in thermal equilibrium -- hosts all three simultaneously. The dynamical heterogeneity even persists across a thermal phase transition into a long-range ordered nematic phase.
Investigating the dynamics of the ordered phase, we find that the motion of its fractionalized quasiparticles is restricted to an emergent fractal network, leading to subdiffusive yet ergodic transport that deviates from conventional hydrodynamic expectations. The fractal exhibits critical scaling from the lattice scale up to long-wavelengths.
This fractal structure also shapes the distribution of quasiparticle lifetimes, enhancing short-time dynamics. We discuss how this subdiffusive behavior can be probed experimentally in candidate materials through the power spectral density of the magnetization. Indeed, our results account for recent experimental results on dynamical heterogeneity in the spin ice compound $\mathrm{Dy_2Ti_2O_7}$ [arXiv:2408.00460] by identifying generation recombination noise of its fractionalized quasiparticles as the cause of dynamical heterogeneity.
Our results show that dynamical heterogeneity can act as a diagnostic of new cooperative regimes, helping to transcend naive boundaries between equilibrium and non-equilibrium physics and between order and disorder.
| Project | T5 - From localization in quenched disorder to new forms of many-body localization |
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